Speedometer Calibration Question

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Aug 1, 2012 | 09:52 PM

Rusty_S

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From: Houston

Speedometer Calibration Question

I just recently found a Ranchero gauge cluster locally which is in like new condition and was going to pick it up for replacing my falling apart gauge cluster on my 78 Cougar. The problem I have is I thought about just dropping the whole unit in but then I started wondering were all speedometers calibrated the same between 1977 - 1979 or were they calibrated differently? I know I would have to pull the speedometer out of this new housing to roll the odomter to the correct miliage on this vehicle but not sure if I should take my old one and this "new" one to a speedometer shop to have the calibration checked out.

Aug 1, 2012 | 10:38 PM

85e150

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They all use the same series of gears at the trans, both the driven and drive gears, so why would the heads be different? Tire sizes are similar as are axle ratios. I think you are safe with the Ranchero cluster.

Aug 1, 2012 | 10:41 PM

Rusty_S

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From: Houston

Quote:

Originally Posted by 85e150six4mtod

Ah ok that was one thing I was worried about, I know I will have to figure out how to roll this odometer from 30k to 74k like mine reads and I will have to figure out how to get the trip odometer drums out, the central drum the white numbers are worn off unless a speedometer shop can repair the drums for less.

Got to take it apart anyways to check on the color filters make sure their all there or in good shape so might as well try to make the gauges look as nice as I can.